Donburi is just a bowl of rice with your choice of topping. The possibilities are endless. The basic step that's common to all donburi is to steam your rice, short grain Japanese rice if you want to be traditional. From there, you top it with the protein of your choice. If you wanted to make gyudon, you'd stir fry sliced onions, thinly sliced ribeye and finish cooking by simmering in dashi, soy sauce, mirin, sake and sugar. When the meat is done and the sauce slightly thickened you pour it over a bowl of rice and garnish with pickled ginger. I also like it with a raw quail egg to be cooked in the heat of the rice and meat, but really the toppings for donburi are endless.